{
  "id": "0803.1351",
  "version": "v2",
  "published": "2008-03-10T07:40:19.000Z",
  "updated": "2008-07-22T06:06:51.000Z",
  "title": "Defect generation in a spin-1/2 transverse XY chain under repeated quenching of the transverse field",
  "authors": [
    "Victor Mukherjee",
    "Amit Dutta",
    "Diptiman Sen"
  ],
  "comment": "5 pages, 3 figures",
  "journal": "Phys. Rev. B 77, 214427 (2008)",
  "doi": "10.1103/PhysRevB.77.214427",
  "categories": [
    "cond-mat.stat-mech",
    "quant-ph"
  ],
  "abstract": "We study the quenching dynamics of a one-dimensional spin-1/2 $XY$ model in a transverse field when the transverse field $h(=t/\\tau)$ is quenched repeatedly between $-\\infty$ and $+\\infty$. A single passage from $h \\to - \\infty$ to $h \\to +\\infty$ or the other way around is referred to as a half-period of quenching. For an even number of half-periods, the transverse field is brought back to the initial value of $-\\infty$; in the case of an odd number of half-periods, the dynamics is stopped at $h \\to +\\infty$. The density of defects produced due to the non-adiabatic transitions is calculated by mapping the many-particle system to an equivalent Landau-Zener problem and is generally found to vary as $1/\\sqrt{\\tau}$ for large $\\tau$; however, the magnitude is found to depend on the number of half-periods of quenching. For two successive half-periods, the defect density is found to decrease in comparison to a single half-period, suggesting the existence of a corrective mechanism in the reverse path. A similar behavior of the density of defects and the local entropy is observed for repeated quenching. The defect density decays as $1/{\\sqrt\\tau}$ for large $\\tau$ for any number of half-periods, and shows a increase in kink density for small $\\tau$ for an even number; the entropy shows qualitatively the same behavior for any number of half-periods. The probability of non-adiabatic transitions and the local entropy saturate to 1/2 and $\\ln 2$, respectively, for a large number of repeated quenching.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2008-07-22T06:06:51.000Z"
    }
  ],
  "analyses": {
    "subjects": [
      "05.70.Jk",
      "75.10.Jm",
      "73.43.Nq"
    ],
    "keywords": [
      "transverse field",
      "transverse xy chain",
      "repeated quenching",
      "defect generation",
      "half-period"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "publisher": "APS",
      "journal": "Physical Review B",
      "year": 2008,
      "month": "Jun",
      "volume": 77,
      "number": 21,
      "pages": 214427
    },
    "note": {
      "typesetting": "TeX",
      "pages": 5,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2008PhRvB..77u4427M"
    }
  }
}